Which U.S. corn counties are most exposed to drought right now?
The U.S. Drought Exposure Monitor maps roughly 90 million planted corn acres against the U.S. Drought Monitor's weekly severity map. The corn view is a county-by-county picture of where the most corn ground sits under active drought right now, and where conditions are headed over the next three months — refreshed every Thursday.
Where U.S. corn is grown
Corn is the largest row crop in the United States by planted area. About 90 million acres go in the ground each spring, concentrated in a band running from Ohio through Illinois, Iowa, Minnesota, Nebraska, South Dakota, and into eastern Kansas. Iowa and Illinois alone routinely account for roughly a quarter of national planted corn acreage. Outside the Corn Belt, material corn acreage shows up in the Mid-Atlantic, the Texas High Plains, and irrigated parts of the western U.S.
That concentration is why drought timing matters as much as drought severity for corn. A dry spell that hits the western Corn Belt in July — corn's pollination window — can move the national balance sheet in a way drought in a smaller-acreage region cannot. The Monitor's watch list reflects this scale effect: it ranks counties by drought-weighted planted acres, so a severe drought reading across a one-million-acre Iowa county weighs more heavily in the national picture than the same severity reading in a small specialty-crop county.
How the corn view works
The headline view shows planted corn acres as columns colored by current U.S. Drought Monitor severity — hard data only, with no insurance assumptions. The watch list ranks counties by drought-weighted planted acres: planted acres multiplied by severity. A "Forecast Drought" view nudges current conditions by NOAA CPC's Seasonal Drought Outlook to show where the next three months point, and a "vs Last Year" view tracks the change in severity year over year.
Corn is one of the most heavily federally insured crops in the country — in major Corn Belt counties, participation typically runs around 85% of planted acres — so insurance is not the story for corn. Where it helps to know, the Monitor shows a per-county footprint across all federal crop-insurance programs, with crop-insurance acres, grazing and forage acres, and rangeland listed separately and never summed, since a single field can carry more than one policy.
The inputs are the same the rest of the tool uses: planted acres from USDA NASS, current drought severity from the U.S. Drought Monitor, the NOAA CPC outlook for the forecast view, and insurance context from USDA RMA's Summary of Business. Corn appears on its own tab in the live tool.
Data sources for corn drought exposure
Every input behind the corn view is public, free, and refreshed on a known cadence:
| Source | What it provides | Refresh |
|---|---|---|
| USDA NASS | Planted corn acres by county, with three-tier waterfall for current-year coverage | Annual + intra-year revisions |
| USDA RMA Summary of Business | Per-county insurance context across all federal programs — crop insurance, grazing/forage, and rangeland shown separately | Monthly mid-year + crop-year close |
| U.S. Drought Monitor | Current drought severity (D0–D4) by county | Weekly, Thursdays |
| NOAA CPC Seasonal Drought Outlook | 90-day forward outlook — development, persistence, improvement, removal | Monthly |
Frequently asked questions
Which U.S. counties grow the most corn?
Iowa and Illinois lead in planted corn acreage, with Nebraska, Minnesota, Kansas, South Dakota, and Indiana next. At the county level, the largest corn counties cluster across the western Corn Belt — central Iowa, northern Illinois, eastern Nebraska, and southern Minnesota. Outside the Corn Belt, material corn acreage shows up in the Mid-Atlantic, the Texas High Plains, and irrigated parts of the western U.S.
How much U.S. corn is under drought right now?
It changes every week. The Monitor reads current U.S. Drought Monitor severity against USDA NASS planted corn acres county by county, then ranks counties by drought-weighted acres — planted acres multiplied by severity. Because corn is the largest U.S. row crop by planted area, at roughly 90 million acres, even a moderate drought reading across the Corn Belt puts a large absolute acreage under stress. The current week's totals are on the live tool.
Does the corn view account for federal crop insurance?
The drought view is built on hard data only — planted corn acres from USDA NASS and current severity from the U.S. Drought Monitor — with no insurance assumptions. Federal crop insurance appears separately as per-county context drawn from USDA RMA's Summary of Business, showing the footprint across programs. Corn is among the most heavily insured U.S. row crops, so this context is steady; it is shown alongside the drought picture rather than folded into it.
Where is U.S. corn most at risk from drought this week?
It changes weekly. The Monitor reorders its corn watch list every Thursday after the U.S. Drought Monitor publishes. Historically the western Corn Belt — western Iowa, Nebraska, and the Dakotas — draws the most exposure when summer drought develops, while the eastern Corn Belt across Illinois, Indiana, and Ohio tends to be wetter. The current week's view is on the live tool.
Other crops
Each crop has its own geography, its own planted footprint, and its own drought-stress window — so the watch list for one rarely lines up with another.